Substrate processing apparatuses that perform various types of processing on substrates have conventionally been used in the process of manufacturing semiconductor substrates (hereinafter, simply referred to as “substrates”). For example, Japanese Patent Application Laid-Open No. 2010-93230 (Document 1) discloses a batch-type substrate processing apparatus that processes a plurality of substrates by one operation. With the substrate processing apparatus in Document 1, a plurality of substrates held in a horizontal posture and arranged along the thickness (hereinafter, referred to as a “thickness direction”) of the substrates are carried into the apparatus by a batch hand. Then, a posture changing mechanism changes the posture of the plurality of substrates to a vertical posture at once and then collectively transfers the substrates to a pusher. This substrate processing apparatus includes a substrate-direction alignment mechanism for aligning the directions of a plurality of substrates that are held in a vertical posture by a chuck. The substrate-direction alignment mechanism aligns a plurality of substrates so that the orientations (i.e., circumferential positions) of notches provided in peripheral portions of the substrates match one another.
Japanese Patent Application Laid-Open No. 2008-78544 (Document 2) discloses an example of the structure of a substrate alignment apparatus. This substrate alignment apparatus aligns a plurality of substrates by rotating the substrates held in a vertical posture via a driving roller and stopping the rotation when a notch of each substrate has engaged with an engagement shaft that extends in the direction of arrangement of the substrates.
By the way, substrates to be processed by a substrate processing apparatus may be warped under the influence of processing performed before transport to the substrate processing apparatus. The sizes in the thickness direction of warped substrates are larger than those of flat substrates. Thus, the substrates held in a vertical posture by, for example, the pusher of Document 1 may excessively approach or come into contact with adjacent substrates. While the aforementioned batch hand supports two side portions of the substrates in a horizontal posture from the underside, it is difficult for the batch hand to stably support and transport warped substrates.